Q: iPhone 6 WiFi Problem! Help Please!!

I am having issues with my WiFi now from over a year. This thing started when i first upgraged to ios 9.1 Or higher, i don't remember but yeah then after that i was having problems with less wifi signals even if the routewr is in the same room. It doesn't search all the routers around me which other phones can do easily, like i have another phone. My friend'd phone are getting more wifi networks in a single place than me and i am getting less. First i thought its a software problem but i am not sure about it. Now it became a big problem to me, sometimes it's irritating that it doesn't search wifi if i move out of the room which is not too much distance. I am out of warranty now. If somebody has a solution or they having the same problem, can give me suggestion.